Filter bed cleaning



1945. P. B. STREANDER FILTER BED CLEANING Fild Feb. 14,. 1941 5 Sheets-Sheet l IN VEN TOR.

BY v/ W P. B. STREANDER FILTER BED CLEANING Nov. 20, 1945.

s Sheets-Sheet 3 Filed Feb. 14, 1941 P ZZZQ) 18.

INVENTOR. @rearzaen Q5 flay Nov. 20, 1945. P. B. STREANDER FILTER BED CLEANING Filed Feb. 14, 1941 5 Sheets-Sheet INVENTOR.

Nov. 20, 1945. .P. BVSTREANDER FILTER BED CLEANiNG Filed Feb. 14, 1941 5 SheetsSheet 5 .r J M m QM m Patented Nov. 20, 1945 TENT OFFICE FILTER BED CLEANING Philip B. Streander, MaplewooiN. J. Application February 14, 1941, Serial No. 378,931

19 Claims.

This invention relates to filter bed cleaning, and more particularly to filter bed-cleaning means adapted to travel over and through the filter bed to agitate the same and remove the solids retained in the filter bed during filtering operations and to reclassify the filter bed material after such cleaning. The main object of the invention is to provide for novel, advantageous and thorough cleaning of the filter bed.

Another object of the invention is to provide novel and advantageous cleaning means with a positive action throughout the 'full depth of the filter bed whereby it is possible to Withdraw the extraneous solids from the full section of the bed.

It has heretofore been known to wash the top of a filter bed or to provide nozzles extending down into the filter bed, but so far as I am aware it has not been known in movable filter bed cleaners to positively lift substantially all of the filter material in the bed, to scour and wash it while so lifted and to regrade the material as it is replaced in the bed. One of thenovel features of my invention is to hydraulically lift all of the filter material from the bed, wash and scour it, and reclassify or regrade it in one operation. To this end I provide a plow the full width of the bed and of a height corresponding to the depth of the filter material, which plow moves laterally through the bed; The plow is provided with jets which undercut the filter material in front of it, and redeposit it, after washing and scouring, behind the plow. I also provide a caisson or hood over the plow to confine the washing and scouring to the immediate vicinity of the plow and to collect and remove dirty water.

One object of my invention, therefore, is to positively wash and scour substantially all of the material in the filter bed.

Another object of the invention is to provide an improved means for reclassifying filter bed material after such cleaning.

A still further object of the invention is to provide a relatively small filter cleaning apparatus which moves over and through the bed, picking up and agitating substantially all of the material of the bed to dislodge'dirt and other extraneous solids therefrom, and to reclassify and replace the filter bed material after such cleaning.

In carrying out the invention, use may be made of a settling tank, or a fine screen, whereby a certain part of the sludge or foreign solid matter may be removed, before removal of additional solids by filtration, the period of time required for these two operations being decidedly short compared with the long periods required to produce ports,

the same effect bysettling alone, or by the fineness' of screen and size of. screening plant that would otherwise be required. Suchremoval of solids may be'efiected with, or without, theuse of chemicals or other extraneous substances;

The filter maybe composed of any suitable'fine grained material such as a silica-sand, a fine coal, crushed stone or marble, orany other granular material suitable for the filter medium. The filter media maybe mounted on a perforated plate, or a suitably supported and reinforced wire mesh. The filter bed may be-o-f the depth required to remove the solids but, for most applications,

this would probably be not less than 6 inchesnor more than 12 inches. The filter bed may take whatever form is required to economically build the unit and may be built around the periphery of a circular settling tank, or it may be built asa separate unit in which case it may be rectangular in shape, or it may be contained with an annular channel between two concentric walls.

In substantially all instances the filter would comprise an upper chamber to receive the liquid to be filtered, a filter medium, and a lower chamber to receive the filtrate. Further, the arrangement may be such that liquid can be by-passed around theupper chamber directly into the lower chamber without passing through the filter bed.

This may :be done by providing movable diversion gates, in the influent channel to the filter bed, that can be lifted, allowing the liquid to flow directly into the lower chamber. The purpose of the by-passing may be to fiush out the lower chamber by passing the liquid through restricted at a high velocity, and collecting it at the opposite side of the bed in the outflow or effluent channel. The filter bed may also be provided with an overflow effluent weir of the liquid through the bed and to maintain the liquid over the filter bed at the depth of. liquid required for operation of the bed and the cleaner.

Provision may also be made as heretofore to mount the cleaner mechanism on a suitable traveling bridge or carriage, arranged over the filter compartment, by means of which the cleaner is made to travel over and through the filter medium, so that, when in use, the retained solids may be continuously or intermittently removed. The cleaner bridge may be mounted separately on rails as inStreander No. 2,086,829, July 13, 1937, or it may form a part of other mountings as in Lose Patent No. 2,235,227. When the liquid rises to any predetermined level over the eflluent or control weir, suitable devices are, or may be, shifted, as by float control such as shown in said to control the flow Streander patent, causing the movement of the bridge or carriage, on which the cleaner is mounted, over the filter compartment. Suitable controls are inter-connected with the float switch, or other control use, to make the cleaner operative.

Other objects, features and advantages will appear upon consideration of thefollowing description and of the drawings in which:

Figure lfimarverticah sectional elevation: of as form of apparatus ladapted to travel tin OnQ'direction only, as, for example, a cleaner for an annular filter bed.

Figure 2 is a vertical sectional elevation of a.

modification of the plow or barrier shown'in*1 ig ure 1, and having two rows of upwardlyginclinedzl nozzles.

Figure 3 is a small scale, partial plan vi'ew 0f? a circular settling tank surrounded by areannua lar filter, such as a structure in which the cleaner of Fig'ured is designed tozo erates Figure 4 iis a partlaliverticali sectionalaviewaofm the combined settlmgandfiltecingetank showmimz Figure "3, together witliawleane'naimplaiceri Figure "5 is a verticatfcrossasectional elevationo of another 'embodimentfofifltherinventionfmch is designed to tr a'vel in both directionseas fOI'illSE-EE- in arecttifgulalrfilterv bdfi Figure -B 'is an enlarged perspeotiveiviewapantly i insectioniof the*embcdiment shown iniFigureaaf.

Figure"? a partial plahlviewrpamly in sec-L tio'n, 1 of a rectangular filter utilizmg aedevice tofu the 'type shown in Figures-5 aand-i. takehralongzz the planes designated-my the lihes- 4-7 foL'Figures 8,"tdgether with a cle aner in o riera'tingaposrti'onrl.v

Figuret isa longitudihal ver tical asisadaptdfdr-use in a-ciicular or annular filter: 451

izi'which the cleaner,-" I U, moves iflrone 'dire'ctiumi (i'n' 'thediawirigehbwn as t6 the3eit1only The cieanerds showii ifi an :operating position ineaa -iilter bed-' l f ofdiscrete materiai wliicliiis sap ported "by a perfdrated plate l 2,: and thesuppen'rw surface ofwhicl'i is designated by I 3? Thel'cleanen III "comprisesa c eaner-macro plow Id ot the full?) filterbed dpth' and a classifier ahead ori'cadssonu I 'Ih'e caissonis qarefrablyzso constructdiase to provide a=rearwardly s16ping front face IIIrear walli'l 8$and end I 93"- It' is preferred-that the-caisson? orh'oodf l5 exterid the entireA'Widthiu of 'theifilte'r bed-I l fee as td'provide 'fdr thorough cl'dfl'ilig of all of the bed I iri' one passage Of -lih upper reams of-"th'e plow f" to the depth of the filter medium II. It is also preferred that the forward, or leading, face 24 of the cleaner head I4 be inclined toward the rear, as shown, in order to facilitate the lifting of all of the discrete filter material over the plow so that it can be thoroughly washed and cleaned. The interior of the cleaner head I4 provides a distribution conduit 25 leading from an inlet pipe 26, which pipe supplies liquid under pressure to a:rowof:-:0rifices: or nozzles :21- dischargingr downwardly from-the lower leading edge ,of:.the cleaner head I4 and an upwardly discharging row of nozzles 28 in the lower portion of the leading face 24 of the cleaner head. Although only one row of upwardly-=discharging nozzles 28 is shown in Figure x41, it should be understood that a plurality of rows at difirent heights may be used, as shown in Fi'g'ure 2; in which an upper row of upwardly dischargingnozzles 29 is shown on the leading face 24 of the head at an intermediate level thereof; j Am .outlet piper 30 2 leads ..from-= the -'.classifir head :I 5 r-fo rzthe;pu r1: oselofdaakingiawayztheiwaste liquid containingzwthei SOIidSiI'Gl'HDVBd fromi the materialiofsz the-=filter: bed: ASJEShQWIIJlHiLthBL drawingsi-zthe :outletapipe 23E] ileadslfrom' aicollecta ing zchamb'era 3 t; which: communicates with :thB: upper'portiontofcthezcaisson, or5hoodi4l 5 thtougha spaced :ports.c32.i 'Ihemlassifier head 15 zhasia-lso adjustable sandr.shoes. 33- and .34 at thesloWer edgesof theifront 'an'dciback walls nee-ensue: to confine the; cleaningzactioncwithinthe :limit's-ot the: classifier; head iandnto:levehthe sand asthe: clean'enpa'sses over therfiiter :bed;-.. The classifii head I5 and'thecleanerrh'ead :14 are molmted're spe'ctive'ly over? and in ntheafilter: bed :"I I by 1 any suitable meansfrom-aparriage-zas shownzzin Fig ure '4;a adapted to :horizontallyvmovethe -cleaner head I 4,? through, and-"the caissonr I5iover; the filter: bed, th'e sclassifi'er: heada orscaisson I55 -andipldw;on cleanenzhead i1 4 .movei td the left';las shown inzth'es figure, the ssandushoesifia and-s42 ridevaIonguthe-(top l3cofsthe bedqland the water: under-"pressure flows throughth'e inlet pipe 2 E in to :the :plow or pl eanerfhead 4 'and is -disch'arged thirough the rows'of orificesmnnozzls -2 Rand 2 8. The waterspassing out of the downwardlyipoirib ing'inozzles 21 loosens 'up' the bed close =to= the screen"- or perforated plate -'-I 2 and= :the :sand th'us loos'ened is passed upwardlyab'y means ofi the up ward'lwdirecte'dinozzles: 2 fifalongzthe for-ward side f of" the ,cleaner head r I I soasto pass oven-the top"- oflsaid head rand :fall: :tmthe rear thereof f Obvi ouslyy'the -larger 'and"-heavier"particles fall-l first, thuswclassifying z vthe material in layers; as shown: in the figure in which the-lowerdotted' line iifi designates the' uppers uimrt of the coarser and heavier: filterr partielescand the upper-dine 3 5 ds ignates the upper limits otth'e lighterof such panticles.

The *clanershowmin Figures'li'i and-Eds thesame in principle as .theronez'shown'in Fi'gure'lj excepting-r that itxis used: for .a two directional travel: Thefisti'uctureofthis'type of- 'cleaner cliffersrfromiithat rshown in Figure l'on'ly *in" those DaIESYWhiOHJ-iCiS desirable to'changewhenth'edirection'of movement of=the-cleaner --is reversed fromztime to time: The cleaner head lcis pref erably provided with .bOth faces dl an-d-f lz 'in cli'nedf as shown: E'a'ch face is provided- 'with downwardly pointing orifices or nozzles 2T0!- and 21b": respectivelyj: andz at '1 least. one row of up wardly directedfdischarge jets 28d and 2 8b re spectively the same as theleadihg 'fa'ce "of the one=way'cleaner:* The caisson; or h'oodi 75similarrin1:construction to -that of Figured; al

and passes a large ter will be by-passed through the though both faces may be sloping,iif desired, as shown in this figure. In addition'to these parts which are similar to those of Figure 1, there is shown in Figure a divisional wall 43 which separates the cleaner head Ml into two chambers 44 and 45, the forward one of which will serve as the distribution conduit connecting the supply pipe '26 to the cleaning nozzles then in operation. Figure 5 shows a two-way cleaner as, moving toward the left, in which event the left-hand chamber 44 would be utilized. to supply water under pressure to the left-hand nozzles 21a and 28a,-while there would be; at most, a relatively small fiow through the righthand chamber 4 3 and its orifices 21b and 281). Each chamber of this cleaner head is also desirably provided with a separate, or branch, pressure liquid pipe connection 26a and 26b which connect the two chambers 54 and t5, respective.- ly, to the inlet pipe 26. The branch pipes, 26a and 261), will be provided with suitable means for selectively connecting the inlet pipe 26' to one or the other'of the distribution chambers 44 or 65, depending upon the direction of travel of the cleaner. Several such means are known, but for purposes of illustration I show valves 45a, in branch conduit 25a, and 45b, in branch conduit 2%, each of which is operated by a solenoid 46a and 46b respectively. The two s'ole noids 46a, and 46?) should be so interconnected that when one is operated to open the valve connected to it the other will be its valve-that is, when one solencid'is energized the other is deenergized. It is preferred that some means be supplied to provide a very slight flow through the trailing chamber, the right-hand chamber 45, when movement of the cleaner is toward the left as indicated by the arrow in Figure 5, in order to prevent settling filter material from falling into some of the upwardly pointing nozzles 28b and thereby clogging them; Various means for securing such a minor flow could be utilized, but for purposes of illustration I show' a bleeder pipe 4'! leading fromthe main inlet pipe 26 and branching into both branch supply pipes, 26a and 26b behind the solenoidoperated' valves 45a and 45b. Preferably such ableeder pipe will be provided with a valve'Ml to adjust the amount .of flow therethrough. Thus, when one valve, such as 45a, is opened by its solenoid flow of wash water into one as M, a small flow of wableeder pipe 41 into the trailing chamber #5 and out the nozzles Zlband 2%, so as to prevent grains of filter material from becoming lodged therein. Such a bypass flow Will be large enough to keep the nozzles clean but small classification and redepositingof the bed material. Obviously, the solenoids 46a and 45b will be energized alternately as the cleaner reaches of the chambers, such one end or the other of the paths controlled by h th cleaner head. v

The pressure liquid for both types of cleaner heads is supplied by means of one or more pressure pumps 55) driven by a suitable motor 5! mounted on the travelling bridge supporting the cleaning mechanism. The waste water, containing the solids removed by the cleaner, is pumped out of the classifier head by means of one 'or more waste water pumps 52 able motor 53 and is passed through waste water pipe 5 3 to any desired location.

Figures 3, 4, '7, 8 ferred arrangements of the filter beds and of the operated to close enough to avoid disturbing the driven by a suit-' and 9 show several of the preis suported on the perforated plate I2 in the filter chamber Bl surrounding the settling tank 60.

In this form the liquid spills over a weir 62 and i into the upper part of the filter chamber 6!. It then flows through th filter bed II and perforated plate I2 into a lower chamber'GZa and then through effluent ports 63 to a channel 54. From here it spills over an efliuent weir 65 into the effluent channel 66. ihe purpose of the effluent weir 65 isto maintain the liquid level over the filter at such an elevation as will provide the best filtering and cleaning results. The intermediate channel 64 is desired as it provides a body of clean water that can be used to clean the filter. This can be accomplished by extending the inlet pipe'55 of the pump 50 into this channel so as to withdraw the necessary water for cleaning. In this embodiment the cleaner, pumps and motor are carried on arevolving bridge 56, the peripheral end of which is carried by a wheel 51 riding on a rail 58 afiixed to the upper portion of the tank wall, and the other end of which is supported by suitable means not shown. Such'a bridge can be also utilized to carry sludge scrapers, not shown, and can be constructed according to well known practice. The cleaner head l4 and the caisson or hood l5 are rigidly held in. spaced relationship to the-perforated plate !2, which supports the filter bed i l by any suitable means, such as rods 59. In most installations, in view of the small size of the filter cleaner and its as-- sociated caisson or hood, it will be desirable to permanently place the filter cleaner in the'filter bed although it would be obvious that an elevating means could be utilized to withdraw the head from the filter bed when not in operation and to lower it into the filter bed when it is desired to suitable place, such as the inlet to. the settling basin 60.

Figures 7, 8 and 9 are views of a rectangular filter bed. In this form the liquid enters the influent fiurne in through a pipe H or any other suitable form of liquid entry. The liquid enters the filter H through'a series of ports E2, or by other means of entry, flows through bed I l, perforated screen I2, into a collecting chamber 13, and thence'through effluent ports 14 into the common channel 15 and over effluent Weirs I6 into the effluent channel l1. ed a reversible travelling bridge that supports and mounts the various parts of the'entire cleaning mechanism, The bridge comprises a suitable framework Si in which are journaled wheels, 82

extend longitudinally of riding on'rails 83 which the filter chamber 84. The bridge supportsthe wash water pump 59 and its motor 5!, the waste water pump 52 and its motor 53, and the cleaner head M and caisson 55, by suitable means, such as hangers 0r supports 35. The waste, or dirty, water may be discharged through the waste water pipe 54 into any ing trough 86, which returns waste water by means of pipe 81 into any suitable place such as a preceding settling basin, not shown.

In addition there is also shown in Figures '7, 8

and 9 an arrangement for by-passing liquid from Over the filter bed is mount suitable place, as into collectthereby zseparatingandz placingsin the-ainfluentrfiume 'loeiintosandcflushingsout the lowerrcompartment flimfjthefilter chamber: For: this-:there-isl'shown :drainage gater9 Bz'finrthecoma mom infiuent :iflum i 1 1 delivering: watersintc at:

distributing; channel 91; which: is 7 connected: to. 1

placed incoperation thetcleaning headz I 4 is-movedi 201' through the filter vbed I I: At; the same: timethe pressure iliquidv-pumpgfw andthe-twaste litjuidi pump;52--.-are-; automatically startedr. ThETPIESE sure liquid pump supplies-liquidundenthe required: pressure to the 'oleanenhead :1 4 sure liquid pipeQB:

pressure water issues from? the cleaner head-througlrithe nozzles :21 -and-i2$in the lower v portion of -the cleaner headii These nozzleszarei so iarrangedathat -the--lower--.ones 2c! issuanceeofvjetsksof liquid at= aaxhigh velocity: for wardly and against the supportin plate-2| 2; which serves:to undercut and:suspendiithe part of the: bed-'dmmediatelyvahead thecleaner head:

upper jetsr28are;so:-arranged:that:-they will causes the=issuance OfzjfifiS of: liquid at -a-high-velocity1"- alongigandr generallyiparallel toi:therinclined-iface'e Zl-ofrthe cleanecheada The rcombined actionzotthese'two setsvof Znoze" zlesasuspendsi the: filter media. the t-the classifienhead! Srand lifts the filter mee dia. overvthewtop ofvthemleanerhead .44: At-the same,-.ti-me the high velocity-oil the: two: sets of water-jets; thoroughlymgitatesthefilter media;

foreigrr solids retained; in-the filter :meduim -dur-r ing- {thee filtering.1roperation.-r The: foreigncsolids" are then separated from the sand in the:classi=, fierrhead;,aby providinigs-ail-rupward flow of-liquid Within" theiclassifierrhead of: keep the 1 foreign matter in high: enough to float thevfilter media:

The.- cleaner :head r l 4 with its; inclined face 25 provides. assolid: barrier-moving cth'rough the full-1* suspension; but-not? dpthrof rthezfilterv media th'e-rhydraulic actiorriof'i the supper andilower-jets 21 andr28; servingito sus pend; agitate :anddift theasand; from the-forwards side-ato-the rear-siderof the cleaner:head Mm. Iii: thisilifting-'and iagitating of the-filter, bed 'matee suspensionthee sufiicient'velocity to W valves:

halfzbeingzprovidedcwith nozzles-12in amt 282mm:- one-haltiandizmsand. ZBbIfoKthe.oppositeolialfn When .travelling:toward itheeleftz pressure-water: is, suppliectztmthe:lefti handiside ofzthe cleaner? head byra separate pressure waterspiperzfimzand r thisiwater issues ;through: .HGZZlSiiZld' andhZBaa: When. the travel is reversedipressure waters-is plie'd-tto :the righthand side 'by@the pressureewaten: pipev-26b-sand-issuesrthrough; nozzles zlbran'd 2811i, The" change from: supply of.-"pressure: a liquid by pipe 125a :to supplysby pipe 2fi'brrmay 'bea-accOmE- plishediby placing in: each pipesaisolenoi'd-opers ated valve-which valves s are '.-so i wired ithatsuponzrz change onicleanienndirectionz oneavalve is; openedri i and theother :valve is'closed:

Minute partioles'iofrforeign' solids.::that pass; through the zfilter. media: may. dodges in: the lower chamhenof therfilterzbed; Tozpreventclogging: in: the slower; chamber and/on. septizatiomwhem such solids are-ref; organic form; assin -sewageal these:solids:.musttbe periodicalhm removedii Inc the usualatypeeof filter bed 'thisisadonevbymanueallycextendingashose into theechamberscando flushing-zit out with pressure liquid; Or the Ten;

ith'roughithe -pres'-; 2,52 tire ?filter-;medium":amir the'ssupporting; plates carer? removedtand: thelower' chamber-sis:then cleanedac Inrthis: invention::nove1 im'eanscare sprovidedto clearn out the lowerchamber. R'eferringstosl lige uresfl', 8'iand :9; and ithe previous description; this;

diversion s'gates SMare-zprovided Lthatfconneet the: infiuent fiiimet'm to a: seriesroi' pressuremhamhers: 91 under-the infllient: fiumer WhEIlY..thE.-J-IQWEI:$ chamber 1's to :be :cleaned: the=*diversion-: gate=93 515;, closed totstop fl'ow throughrthesfilter andspermitz water. thereimtoi'drain.itherefromn At "thHFSflHIt-Z: time; one :01: more ofr the drainage rgatesiefil' (as sho-mmatzleft :ofrFigure 8) inane-common flume? lll;-are-:opened-.. The-idifversion" gate HS- is' them within :the limitsri raisedr'andrinfluent' liquorcpasses into theidi'strtb-sutingstchann'elss l r Thi's'fis discharged througlnm series of:ports* 92 into the :part :ofzsthe: lower reels lecting chamber- 73i connec-tedato the distributing channeli. The liquidzpasses :bhI'OUghthE-P0ft'5l923 at :a .high velocity and tscours-xand flushesiouti any" sediment contained-: in :theelowert chamhenmthez flushing liquid fiow-ingcth-rough theeflluent ports? T4and intosthev comm-on: channel 75: IfiTthEll'l passes over the weirilfisand inte the eflluent, or?" it may -be returned- -to another pantzof: the..plant: for subsequent-treatment.

The float controlled fswitches referred ftGT-ln "the"? specification'amay be suchwas areadisoldsed int'my-r prior-Patent N0; 2,0861329-andd3he floatecontrol' oft may; beeffectedvby-"opening; and: closing solenoid:operatedi-switchear Ita-wi1l= beeobserved that with 'the's-apparatusit shown androperatingras described ITse-cure-severah improvedfresults; including amore ccomplete rand:

rialsthe entireecleaningraction'ismonfined within 1 6% thorough washing {and-scouring nfith e 'filterlbd the-zlimitsoftheclassifierhead15. Iri the'cleana lng action therlarger particles of the ;filter:mediat t beingyheavier; first fa11';0n:the' supporting: plate-r I 2 and-'areiollowedfbyrotherP s e of :itheir. size, so that When'the *cleaningaction isfi v completedr there is provided a filter mediums= gradedwithrsthe coarsezparticles Y on the bottom andrthe finerparticles on" the top 'ofthe filter bed;

'I'haoperatiolr of "the cleaning-mechanismillus trated 'in Figure 5:is=similar tozthat described for-r the mechanismrshown' in Figure-1 excepting: that. i the cleaner ishown *incFignrefi -is forra-rtwo direc tion travel. Imthisrarrangement. the cleaners head vz lih iSFdiYidGdli-fltflitWOi separate? chambers whereby it:is more eifeotivelyrcleansedandialso as complete 'renewaljorresettingaofzthetbed includ= ing a classifying or grading duringethe'q'esettinge' whereby larger? grains are; below-arid:- smaller grains above in the bed=,: it being welizlmown that: with such-arrangement fi-ltrationzis zmorezeffecttve and+ a-lsor'that' there is "less penetration :of thecbedo by-removedasolids so that-the. .-bed--is:kept irrthete terrcondit-ionz; These 'resultssarmsecuredzbyiak vantageous featuresof oonstructiorrrreferred to i above or apparent on consideration ofrmy dise-- closure: These "features include: the EQIOWSOIjbHJI-i u rier wall extendingflztheswidtitc ofwtheabed and of heightcorresponding"-to the depth ofrthe bednver :andili :byrmeananffthe. dividinguwall: 43;: each: which:thebedlmaterialeis littedduring theiwasm ing'cperation, the undercutting jets along the forward lower edge of the barrier that loosen and raise the bed from the screen,- thus facilitating the forward movement of the barrier and preventing injury to the bed support by the jamming of material under the moving barrier, the placing of additional orifices to provide jets that scour the bed material while lifting it over the barrier, the means for preventing bed material from enteringthrough idle orifices, the hood or caisson which confines the action within a limited area or volume in which cleaning and scouring is fully effective, the classifying and redepositing action as the material falls behind the barrier, and other features and actions.

It should be understood that various changes may be made and that various features may be used without others, without departing from the true scope and spirit of the invention.

What I claim is:

1. A travelling cleaning device adapted to move along a filter bed in which the filter medium is composed of granular material, said travelling cleaning device comprising an open-bottom caisson movable over the surface of the bed, a hollow transverse cleaner head beneath the caisson and movable therewith, said cleaner head being. so positioned that its bottom is closely adjacent the bottom of the filter bed and having a continuous leading face extending substantially these length of said caisson and of a height substantially the depth of said bed, means to supply water under pressure to within said head, orifices through said face at its lower edge and positioned to direct jets of water forwardly and downwardly, whereby the bed material will be loosened and lifted over the head as it advances, and means for removing dirty water from the caisson.

2. A travelling cleaning device adapted to move along a filter bed in which the filter me- 0 dium is composed of granular material, said device comprising an open-bottom caisson movable over the surface of the bed, a hollow transverse cleaner head with a continuous leading face extending substantially the length of the caisson and from the top to the bottom of the bed, aid

head being beneath the caisson and movable therewith, orifices through said face at its lower edge positioned to direct jets of water forwardly and downwardly against-the bottom of the filter bed and other orifice through the lower portion of said face and positioned to direct jets of water upwardly and substantially parallel to said face, means for supplying'liquid under pressure to the interior of said head, and means for withdrawing dirty liquid from the interior of said caisson. 3. A device for the cleaning of a filter bed composed of a granular substance, said device being movable over and through the filter media 7 and comprisinga cleaner head, said cleaner head being hollow and having a rearwardly and upwardly inclined leading surface of a height approximating the depth of the bed, two rows of discharge orifices through the leading surface of said cleaner head, one row of orifices along the lower edge of said surface being positioned to direct discharge therethrough forwardly and downwardly toward the bottom of the bed, the other row being positioned above said first row to direct discharge therethrough upwardly and 7 substantially parallel to said inclined surface, means to deliver liquid under pressure to within the cleaner head, and means for withdrawing dirty liguidfrom adjacent the cleaner head. 7

4," A device for the cleaning of the filter media of a filter bed composed of granular substances, said device being movable over and through the said filter media and comprising a hollow'cleaner head having a continuous leading face of a length approximately the width of the bed and of a height approximately the depth of the bed, a plurality of orifices through the lower part of the said leading face of the cleaner head so positioned as to direct discharge therethrough forwardly and downwardly against the material at the bottom of the bed, whereby the filter material in the lower part of the bed in front of said head is undercut and suspended in liquid, a plurality of other orifices in. said leading face so positioned as to direct discharge therethrough upwardly and generally parallel to the face of the cleaner head, whereby the filter media on the front side of the cleaner head is lifted over the head and to the rear thereof, means for supplying liquid under pressure to said head, means for collecting liquid discharged from said orifices, and means for removing dirty water from the col lecting means.

5. A device for the cleaning of the filter media of a filter bed composed of a'granular substance of varied size carried on a filter bed support, said device being movable over and through said variable size filter media and comprising a cleaner head having a leading face of a height approximating the depthof the bed and a length approximating the width of said bed, said cleaner head being hollow and having discharge orifices through said face so positioned at the lower edge thereof as to direct discharge therethrough downwardly and forwardly at an angle against the filter media support, whereby the filter media adjacent such support is undercut and suspended in liquid, other orifices through said face so positioned as to direct discharge therethrough generally parallel to and upwardly along the face of the cleaner head, whereby the filter media in front of the cleaner head is scoured and lifted over the head and to the rear thereof and the varied sized filter media is deposited in graded layers with the coarse particles on the bottom and the finer particles on the top of the filter bed, a caissonover said cleaner head, means for supplying liquid under pressure to the interior of said cleaner head,and means for removing dirty liquid from the caisson.

6. A reciprocable device for the cleaning of the filter media of a granular filter bed, said device being movable over and through thesaid filter media andcomprising a cleaner head of a length 5 approximately the. width of the filter bed and of a height approximately the depth of the filter bed, said head beinghollow and divided into two longitudinal compartments with upwardly and rearwardly inclined outer faces, means including discharge orifices through said outer faces, some of said orifices being located along the lower edge of each face and positioned to direct discharge therethrough outwardly and downwardly and others of said orifices being positioned to direct discharge therethrough upwardly and substantially parallel to said faces, whereby the filter media at the leading face is agitated and caused to pass over the cleaner head, a carriage supporting said cleaner head in said filter bed with its lower portion adjacent the bottom of said filter bed, means to move said carriage longitudinally of said bed, means for reversing the direcdeliver liquid under pressure to within each of said chambers.

15. In a device for cleaning a granular filter bed, said device being movable over and through the filter bed, and including a plurality of discharge orifices movable through the bed and means for withdrawing dirty liquid from adjacent said orifices, an improved cleaner head comprising a hollow transverse plow extending from adjacent one side of said bed to adjacent the other side and from adjacent the bottom of said bed to adjacent the top thereof, said plow having a continuous leading face for the full length and height thereof and a row of orifices through said face positioned to direct discharge therethrough forwardly and downwardly ahead of said plow, and means for delivering liquid under pressure to the interior portion of said plow.

16. In a filter bed cleaner of the type which is moved over and through the filter bed to wash dirt from the filter medium, means for lifting material from a section of the filter bed from its support and washing, during such lifting, and for redepositing on its support and classifying during such depositing, such lifted and washed material, said means comprising a rearwardly inclined wall of a length approximately the width of the filter bed and of a height approximately the depth of the filter medium, a series of downwardly and forwardly discharging orifices at the lower edge of said wall and another series of orifices through said wall discharging upwardly and generally parallel to said wall, and means for supplying water under pressure to said orifices.

17. A process for cleaning a granular filter bed which comprises discharging a plurality of adjacent streams of water under pressure downwardly and forwardly adjacent the bottom of the filter bed, discharging other streams of water under pressure upwardly and rearwardly from a position above said first mentioned streams, the force of said last mentioned streams being sufficient to carry filter bed material to a level adjacent the top of the filter bed, removing dirty water from said moving material, reforming the filter bed rearwardly of said streams by depositing filter bed material in a quiescent zone rearwardly of said streams, and moving said streams forwardly along the bed until the entire bed has been cleaned and reformed.

18. A process of progressively cleaning and reclassifying a granular filter bed which comprises the steps of undercutting by and suspending in a stream of water under pressure the entire filter bed material in a vertical section of the bed, washing and lifting such suspended material to a level adjacent the top level of the bed by another stream of water under pressure, separating the washed filter bed material by gravity from the water, withdrawing the wash water to waste, progressively moving the streams of water forwardly within said bed to undercut and lift further vertical sections thereof, and simultaneously classifying and depositing washed filter bed material behind the forwardly moving streams.

19. A process for cleaning a granular filter bed comprising progressively isolating narrow transverse sections of the filter bed from downflow of liquid therethrough, dividing the filter bed in said isolated section longitudinally into a forward cleaning zone and a rearward depositing zone, discharging a plurality of streams of water downwardly and forwardly adjacent the bottom of said cleaning zone, discharging a plurality of other streams of water upwardly in said cleaning zone from a position rearwardly of said first mentioned streams, thereby lifting substantially all of the filter bed material upwardly by said streams to a level above the normal level of said filter bed, depositing the lifted material in the rearward quiescent zone, and withdrawing dirty water from above said bed in said isolated section.

PHILIP B. STREANDER. 

